feat: better exception and message for table not found (#851)

closes #796

Author: mesejo

python/datafusion/tests/test_context.py

@@ -466,6 +466,13 @@ def test_table_exist(ctx):
     assert ctx.table_exist("t") is True
 
 
+def test_table_not_found(ctx):
+    from uuid import uuid4
+
+    with pytest.raises(KeyError):
+        ctx.table(f"not-found-{uuid4()}")
+
+
 def test_read_json(ctx):
     path = os.path.dirname(os.path.abspath(__file__))
 

src/context.rs

@@ -765,7 +765,8 @@ impl PySessionContext {
     }
 
     pub fn table(&self, name: &str, py: Python) -> PyResult<PyDataFrame> {
-        let x = wait_for_future(py, self.ctx.table(name)).map_err(DataFusionError::from)?;
+        let x = wait_for_future(py, self.ctx.table(name))
+            .map_err(|e| PyKeyError::new_err(e.to_string()))?;
         Ok(PyDataFrame::new(x))
     }